From 47335eeea8f1d14b7c6a1dd585a25a9166721168 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Date: Wed, 30 May 2018 08:10:35 +0200 Subject: [PATCH] slirp/ncsi: add checksum support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The checksum field of a NC-SI packet contains a value that may be included in each command and response. The verification is optional but the Linux driver does so when a non-zero value is provided. Let's extend the model to compute the checksum value and exercise a little more the Linux driver. See section "8.2.2.3 - 2's Complement Checksum Compensation" in the Network Controller Sideband Interface (NC-SI) Specification for more details. Signed-off-by: Cédric Le Goater Reviewed-by: Philippe Mathieu-Daudé Tested-by: Joel Stanley Signed-off-by: Samuel Thibault --- slirp/ncsi.c | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) diff --git a/slirp/ncsi.c b/slirp/ncsi.c index 7b3fff207a..7116034afc 100644 --- a/slirp/ncsi.c +++ b/slirp/ncsi.c @@ -1,7 +1,7 @@ /* * NC-SI (Network Controller Sideband Interface) "echo" model * - * Copyright (C) 2016 IBM Corp. + * Copyright (C) 2016-2018 IBM Corp. * * This code is licensed under the GPL version 2 or later. See the * COPYING file in the top-level directory. @@ -11,6 +11,23 @@ #include "ncsi-pkt.h" +static uint32_t ncsi_calculate_checksum(uint16_t *data, int len) +{ + uint32_t checksum = 0; + int i; + + /* + * 32-bit unsigned sum of the NC-SI packet header and NC-SI packet + * payload interpreted as a series of 16-bit unsigned integer values. + */ + for (i = 0; i < len; i++) { + checksum += htons(data[i]); + } + + checksum = (~checksum + 1); + return checksum; +} + /* Get Capabilities */ static int ncsi_rsp_handler_gc(struct ncsi_rsp_pkt_hdr *rnh) { @@ -101,6 +118,9 @@ void ncsi_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) (ncsi_reply + ETH_HLEN); const struct ncsi_rsp_handler *handler = NULL; int i; + int ncsi_rsp_len = sizeof(*nh); + uint32_t checksum; + uint32_t *pchecksum; memset(ncsi_reply, 0, sizeof(ncsi_reply)); @@ -130,15 +150,18 @@ void ncsi_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) /* TODO: handle errors */ handler->handler(rnh); } + ncsi_rsp_len += handler->payload; } else { rnh->common.length = 0; rnh->code = htons(NCSI_PKT_RSP_C_UNAVAILABLE); rnh->reason = htons(NCSI_PKT_RSP_R_UNKNOWN); } - /* TODO: add a checksum at the end of the frame but the specs - * allows it to be zero */ + /* Add the optional checksum at the end of the frame. */ + checksum = ncsi_calculate_checksum((uint16_t *) rnh, ncsi_rsp_len); + pchecksum = (uint32_t *)((void *) rnh + ncsi_rsp_len); + *pchecksum = htonl(checksum); + ncsi_rsp_len += 4; - slirp_output(slirp->opaque, ncsi_reply, ETH_HLEN + sizeof(*nh) + - (handler ? handler->payload : 0) + 4); + slirp_output(slirp->opaque, ncsi_reply, ETH_HLEN + ncsi_rsp_len); }